Metallic connection carriers to which metal wires can be attached are described in German Application No. DE-OS34 04 008. The connection carriers each have a slit forming a recess into which the end of the wire is placed. The shape of the slit can be determined both by edges that run parallel to each other and by edges which run at an angle to each other. The slits, which are formed by punching, can have a smooth, a riffled or a corrugated surface contour. The wire end is passed once through the slit provided in the connection carrier. Subsequent forming of the connection carrier to clamp the wire end in place occurs, with the forming taking place in the heated state at a temperature below the melting temperature of the carrier material. In this way, a mechanically strong and electrically conductive connection between the wire and the connection carrier is formed in a simple manner. The wire end is squeezed at the clamping location and takes on an oblong, elliptical cross-section.
Furthermore, it is known from German Application No. DE-OS 36 15 809 that the quality of such a connection, produced by means of a so-called hot-staking method, can be further improved, particularly for very thin wires, if the wire end is passed through the recess several times. In this way, the forces which occur during the attachment process are distributed over several wires, so that each individual wire is subject to less deformation. The recess is slit-shaped and has a widened part to hold the wire end at the end opposite the open end, with the entire recess being formed by punching.
Efficient use of punching is dependent on the material, its strength, the material thickness and the desired slit width. In the case of recesses with an opening width of approximately 0.3 mm, a limit range of economically efficient punching is reached, since in the case of smaller recesses the punches break off after only a few punching processes due to the low sheet metal thickness. Thus, very high tool down times occur or punching is not even possible.